The proposed research will determine 1) if behavioral and developmental abnormalities associated with iron deficiency anemia during infancy can be corrected with extended iron therapy and 2) if deficits persist in school-aged children who had iron deficiency anemia as infants. In our current study, subjects whose iron deficiency and anemia were both corrected after three months of iron therapy also showed correction of their mental and motor test score deficits. Only 36% of all infants in the anemic group, however, showed this pattern of recovery; in the remaining 64%, biochemical evidence of iron lack and deficits in both mental and motor test scores were still evident even after the three-month course of oral iron or intramuscular iron therapy recommended for correction of the anemia for iron deficiency. To pursue these findings, two studies are proposed. Study I is a double-blind randomized controlled study of the behavioral and developmental effects of complete correction of iron deficiency and anemia in infancy. 90 one- to two-year-old infants will be studied: 30 iron deficient anemic infants, matched by age and sex with 30 nonanemic placebo-treated controls and 30 nonanemic iron-treated controls. Their behavior and development will be assessed before and after both three and six months of oral iron therapy. The study will also provide an opportunity to confirm the specific pattern of limitations, particularly in motor functioning, observed among iron deficient anemic infants in the current project. There are two major possible outcomes of the study: 1) an extended course of iron therapy will correct developmental and behavioral abnormalities in iron deficient anemic infants, a result that would require a major reformulation of current recommendations about iron therapy and monitoring of therapeutic response in infants or 2) pretreatment deficits will persist in some iron deficient anemic infants despite extended treatment, indicating that, depending on chronicity, severity, or timing, iron deficiency anemia in infancy may have irreversible effects. In Study II all 191 children in the current cohort will be reassessed at five years of age using psychoeducational, neurological, motor, and behavioral measures that focus on the specific functions that were identified as impaired in our previous two studies. The proposed research will determine the long-term cognitive, motor, and behavioral sequelae of iron deficiency anemia in infancy and the effects of treatment in a group of children which has already been exceptionally well characterized.